Search engines conventionally provide search results in the form of a ranked list. Some search engines, such as a search engine for mobile applications, provide popular search results near the top of the ranked list. But popular generic searches, such as “games” or “tools” in a mobile application search engine, cover a large space and the conventional ranked lists provide no logical structure within the results, which allows a few popular applications to dominate the list, making the results insufficiently diverse for some users.